1. Field of the Invention
The present invention relates to a rollover suppression control apparatus and a rollover suppression control method.
2. Description of Related Art
JP 2005-35451A describes a rollover suppression control apparatus. As shown in FIG. 3 of JP 2005-35451A, according to this rollover suppression control apparatus, under a rollover preventing control, while an absolute value ≡Gy| of actual lateral acceleration is between a rear-wheel-side reference value Gyr and a front-wheel-side reference value Gyf (Gyr≦|Gy|≦Gyf), inner wheel braking force corresponding to the absolute value of the actual lateral acceleration Gy is generated only for an inner rear wheel of a turning direction, so that vehicle height reduction force is generated at an inner rear part of a vehicle body with respect to the turning direction. In addition, while the absolute value |Gy| of actual lateral acceleration is the front-wheel-side reference value Gyf or larger, the inner wheel braking force is kept being generated for the inner rear wheel of the turning direction and outer wheel braking force corresponding to the absolute value |Gy| of actual lateral acceleration is also generated for an outer front wheel of the turning direction, so that yawing moment in an opposite direction to the turning direction is forcibly generated for the vehicle.
In other words, when the rollover suppression control is performed during the left turning of the vehicle, for example, the braking is made for the outer front wheel of the turning direction, so that the lateral acceleration for rollover suppression is generated in the left direction and the yawing moment is thus generated in the opposite direction to the yawing moment resulting from the turning. Accordingly, a degree of the rollover tendency is decreased to suppress the rollover.
In the meantime, when the applied braking force is as high as a friction limit of a vehicle tire, the lateral force for turning is reduced, so that understeer is generated. That is, the traveling direction may be deviated from a desired range due to the braking force applied by the rollover suppression control.